Question

Rafael hits a tennis ball at 20 m/s. It hits the net, 8m away, at a speed of 12 m/s. What was its deceleration (negative acceleration) in m/s²?

A) 0.5 m/s²
B) 1.0 m/s²
C) 1.5 m/s²
D) 2.0 m/s²

Answer 1

To find the deceleration of the tennis ball, we calculate the time taken to travel 8 meters and then apply it to the acceleration formula. The deceleration is determined to be -20 m/s², which is not provided in the options.

Step-by-step explanation:

To calculate the deceleration of the tennis ball hit by Rafael, we can use the formula for acceleration: a = (v_f - v_i) / t. Where: a is the acceleration (or deceleration when negative), v_f is the final velocity, v_i is the initial velocity, and t is the time taken to change velocity. First, we need to find the time t using the formula: s = (v_i + v_f) / 2 × t. Where: s is the distance traveled, which is 8 m. v_i is the initial velocity, 20 m/s. v_f is the final velocity, 12 m/s. Substituting the values, we get 8 = (20 + 12) / 2 × t, t = 0.4 s. Now using the values for v_i, v_f, and t, we calculate the deceleration (a): a = (12 m/s - 20 m/s) / 0.4 s, a = -8 m/s² / 0.4 s, a = -20 m/s². This means the tennis ball decelerated at 20 m/s², and the correct answer is not listed in the provided options.